(a) Field of the Invention
The present invention relates to a blade assembly for paper shredders, more particularly to a blade assembly that eliminates use of partition rings, reduces cost, and enhances assembly efficiency.
(b) Description of the Prior Art
Paper shredders are common office machines. As they have become more and more compact in size, they are used in the home. In general, a paper shredder is provided with a blade assembly that includes two bladed shafts that opposedly rotate in a downward direction so that paper fed into the paper shredder is cut into fine strips to destroy contents of the paper. The shredded paper can be easily compressed to facilitate subsequent disposal. Aside from a housing and a drive motor, the most important component of the paper shredder is the blade assembly. With reference to FIG. 1, a conventional blade assembly includes a pair of intersecting bladed shafts 1 in a juxtaposed manner. The blades 11 of the bladed shafts intersect such that every pair of intersecting blades can achieve a balanced cutting effect. With reference to FIG. 2, the blades 11 are arranged on a polygonal drive shaft 14 and spaced apart by long partition rings 12 and short partition rings 13 to form the bladed shaft 1.
In the above-mentioned bladed shaft, the difference in length of the long and short partition rings 12, 13 is very small (about the thickness of two blades 11 and generally in the range of 1 mm). Hence, it is different for workers to identify which is which. To solve this problem, some manufacturers use colors or size of the diameter to facilitate identification of the long and short partition rings. In terms of precision and quality whether they are made of metal of plastics, the long and short partition rings 12, 13 have to be precisely controlled to obtain surface precision particularly precise thickness. If their surface is not even or the thickness is not right, the length of the blade assembly and the interval between adjacent blades after assembly will not be correct, which may affect the assembly of the bladed shafts in an intersecting manner.
In the conventional blade assembly, the blades 11 on the polygonal drive shaft 14 are spaced apart by the long partition rings 12 and the short partition rings 13 alternately. It can therefore be seen that the conventional blade assembly is more complicated in terms of structure and parts. In case any of the parts malfunction, the entire bladed shaft will become loosened and cannot work properly.